Mycobacteroides immunogenum is an emerging opportunistic pathogen implicated in nosocomial infections. Comparative genome analyses may provide better insights into its genomic structure, functions and evolution. The present analysis showed that M. immunogenum has an open pan-genome. Approximately 36.8% of putative virulence genes were identified in the accessory regions of M. immunogenum . Phylogenetic analyses revealed two potential novel subspecies of M. immunogenum , supported by evidence from ANIb (average nucleotide identity using blast) and GGDC (Genome to Genome Distance Calculator) analyses. We identified 74 genomic islands (GIs) in Subspecies 1 and 23 GIs in Subspecies 2. All Subspecies 2-harboured GIs were not found in Subspecies 1, indicating that they might have been acquired by Subspecies 2 after their divergence. Subspecies 2 has more defence genes than Subspecies 1, suggesting that it might be more resistant to the insertion of foreign DNA and probably explaining why Subspecies 2 has fewer GIs. Positive selection analysis suggest that M. immunogenum has a lower selection pressure compared to non-pathogenic mycobacteria. Thirteen genes were positively selected and many were involved in virulence.

中文翻译：

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免疫原分枝杆菌的比较基因组分析揭示了两个潜在的新亚种

免疫原分枝杆菌 是一种与医院感染有关的新兴机会性病原体。比较基因组分析可以更好地了解其基因组结构、功能和进化。目前的分析表明，免疫原分枝杆菌具有开放的泛基因组。大约 36.8% 的假定毒力基因在免疫原分枝杆菌的辅助区域中被鉴定。系统发育分析揭示了免疫原分枝杆菌的两个潜在的新亚种，得到了来自 ANIb 的证据的支持（使用blast 的平均核苷酸同一性） ) 和 GGDC（基因组到基因组距离计算器）分析。我们在亚种 1 中鉴定了 74 个基因组岛 (GIs)，在亚种 2 中鉴定了 23 个 GIs。在亚种 1 中没有发现所有亚种 2 栖息的 GIs，这表明它们可能在分化后被亚种 2 获得。亚种 2 比亚种 1 具有更多的防御基因，这表明它可能对插入外来 DNA 的抵抗力更强，并且可能解释了为什么亚种 2 的 GI 较少。正选择分析表明，与非致病性分枝杆菌相比，免疫原分枝杆菌具有较低的选择压力。13 个基因被阳性选择，许多基因与毒力有关。